Recently, the development of next generation clean energy has become more important due to the lack of fossil fuel. Among the next generation clean energy, a solar cell is spotlighted as an energy source for solving the future energy problem because it rarely causes environmental pollution and has the semi-permanent life span and there exists infinite resources for the solar cell.
Such a solar cell may include electrodes formed on a silicon substrate having an N type semiconductor and a P type semiconductor. However, if bonding strength between the electrodes and the silicon substrate is weak, moisture may penetrate into the electrodes under the high-temperature and high-humidity condition, so electric conductivity may be lowered. In extreme cases, the electrodes may be delaminated from the silicon substrate. In this case, the efficiency and the reliability of the solar cell may be degraded.